长链B酸离子液体催化油酸酯化制备生物柴油

为了寻找制备生物柴油过程中能有效降低高酸价油脂酸值的绿色催化剂,采用2步法制备了带表面活性的长链B酸离子液体(IL)N,N-二甲基-N-(3-磺酸丙基)十二烷铵对甲苯磺酸盐[n-DodecMe2N-PS][PTSA]),利用FT-IR,1 H NMR,13C NMR,UV/vis和TGA对该新型离子液体结构进行了表征.利用Hammett方法测定了离子液体的酸度函数值.将其用于催化油酸酯化制备生物柴油,结果表明:该长链B酸离子液体具有较高的催化活性.在n(甲醇)∶n(油酸)∶n(催化剂)为1.5∶1∶0.1,60℃,反应3h条件下催化油酸酯化反应,油酸甲酯产率达96.5%.反应结束后离子液体与酯化产物分为两相,产物易于分离,该离子液体重复利用9次,催化活性没有明显降低.因此,长链离子液体可作为利用低价油脂(如地沟油)制备生物柴油的高效绿色催化剂.

Preparation of biodiesel by esterification of oleic acid catalyzed by long-chain B-acid ionic liquid

In order to find a green catalyst which can effectively decrease the acid number of high-acid value oils,a long-chain B-acid-sufactant-conbined ionic liquid(IL),N,N-dimethyl-N-(3-sulfopropyl)-dodecylamonium-p-toluenesulfonic acid([n-DodecMe2N-PS]),was prepared and characterized by FT-IR,1H NMR,13C NMR,UV/vis and TGA.The H0(Hammett function) value of the IL was also determined.The IL as catalyst was applied to the preparation of biodiesel from oleic acid catalyzed.The results indicated that the long-chain B-acid IL showed high catalytic activity.Under the reaction condition of n(methanol)∶n(oleic acid)∶n(catalyst)=1.5∶1∶0.1,60 ℃,3 h,the yield of methyl oleate reached 96.5%.The product could be separated from the catalyst system by liquid/liquid biphase separation at room temperature.The catalyst could be reused nine times without a significant decrease in the activity. Therefore,an efficient and environmentally friendly catalyst was provided for the synthesis of biodiesel from low cost feedstocks such as waste oils.